Repowering

The challenge

Dismantling of four wind turbines

The Groß Sierning wind farm – located right next to the Loosdorf exit on the A1 motorway – has been generating 16.2 megawatts of electricity for over 20 years with its nine wind turbines, supplying 8,000 households. To increase security of supply, it was decided to generate even more power by renewing the turbines. Prangl was entrusted with the dismantling work for the first four wind turbines – in what were at times very adverse weather conditions.

Our solution

Crucial logistics

The client’s plan was as follows: One of the nine original wind turbines will remain in place, five will be replaced by new, more powerful wind turbines, and the remaining turbines will be completely dismantled. This means that, with just six turbines in future, 26.5 megawatts of green electricity will be produced, supplying 22,000 households. For Prangl, this task was primarily a logistical challenge. This is because the removal of the turbine components had to be well planned to avoid unnecessary downtime and the associated costs.

700 tonne telescopic crane

The concept naturally also included the equipment selected for this project: A 700-tonne telescopic crane was the best solution for the great heights and for high-performance double-hook operation. A 130-tonne telescopic crane was to serve as an auxiliary crane. A telehandler with a maximum lifting capacity of six tonnes was designated for use on site to dismantle various plant components. A 3-axle tractor unit fitted with a 4-axle low-bed semi-trailer was also on the equipment list for the delivery and collection of the individual components.

43-tonne rotor star

Well prepared, the Prangl team set to work. The complete dismantling of each of the four wind turbines began with the entire rotor, which was lowered to the ground in one piece together with the hub. Thanks to a second attachment to the hub, the 43-tonne rotor star could be rotated into the horizontal without any problems and then set down. This was followed by the 51-tonne generator and the 18-tonne nacelle – all at a height of 85 metres. The tower sections, weighing 2 x 44 tonnes and 2 x 60 tonnes, were dismantled from the top down with a lifting height of 21 metres per section.

Braving wind and weather

It is clear that weather conditions at this time of year are not always suitable for work of this kind. At first glance, there appeared to be sufficient space around the wind turbines. However, the solid ground required for heavy machinery was limited in terms of where the machines could be positioned. Yet the yellow team braved the lack of space, the cold and snow flurries – only strong winds could stop them from working. Completion of the wind farm is scheduled for May 2027.